Biology Chapter 3 Vocab

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a microscope that uses a beam of visible light passing through one or more lenses to magnify an object

electron microscope

a microscope that fouses a beam of electrons to magnify objects

magnification

the increase of an object's apparent size by using lenses or mirrors

resolution

in microscopes, the ability to form images with fine detail

scanning tunneling microscope

a microscope that uses a needle-like probe to measure differences in voltage caused by electrons that leak, or tunnel, from the surgace of the object being viewed

cell theory

the theory that states that all living things are made up of cells, that celss are the basic units of organisms, that each cell in a multicellular organism has a specific job, and that cells come only from existing cells

cell membrane

a phospholipid layer that covers a cell's surface and acts as a barrier between the inside of a cell and the cell's environment

cytoplasm

the region of the cell within the membrane that includes the fluid, the cytoskeleton, and all of the organelles except the nucleus

cytoskeleton

the cytoplasmic network of protein filaments that plays an essential role in cell movement, shape and division

ribosome

a cell organelle composed of RNA and protein, the site of protein synthesis

prokaryote

an organism that consists of a single cell that does not have a nucleus or cell organelles; an example is bacterium

cell wall

a rigid structure that surrounds the cell membrane and provides support to the cell

flagellum

a long, hairlike structure that grows out of a cell and enables the cell to move

eukaryote

an organism made up of cells that have a nucleus enclosed by a membrane, multiple chromosones, and a miotic cycle; eukaryotes include animals, plants and fungi but not bacteria or cyanobacteria

nucleus

in a eukaryotic cell, biology, a membrane-bound organelle that contains the cell's DNA and that has a role in processes such as growth, metabolism and reproduction

organelle

one of the small bodies that are found in the cytoplasm of a cell and that are specialized to perfrom body functions

cilium

a hairlike structure arranged in tightly packed rows that projects from the surface of some cells

phospholipid

a lipid that contains phosphorus and that is a structural component in cell membranes

lipid bilayer

the basic structure of a biological membrane, composed of two layers of phospholipids

endoplasmic reticulum

a system of membranses that is found in a cell's cytoplasm and that assists in the production, processing, and transport of proteins and in the production of lipids

vesicle

a small cavity or sac that contains materials in a eukaryotic cell; forms when part of the cell membrane surrounds the materials to be taken into the cell or transported within the cell

Golgi apparatus

cell organelle that helps make and package materials to be transported out of the cell

lysosome

a cell organelle that contains digestive enzymes

mitochondrion

in eukaryotic cells, the cell organelle that is surrounded by two membranes and that is the site of cellular respiration, which produces ATP

chloroplast

an organelle found in plant and algae cells where photosynthesis occurs

central vacuole

a large cavity or sac that is found in plants or protozoans and that contains air or partially digested food